The use of transition metals, especially chromium or Group 4/5 metals such as titanium, zirconium and hafnium as catalysts in the polymerization of ethylene is well known. These polymerization reactions may use simple aluminum alkyls of the general formula ALR.sub.3 as cocatalysts.
U.S. Pat. No. 5,777,120 (Jordan et al) discloses aluminum-amidinate complexes which catalyzes the polymerization of ethylene in the absence of transition metals.
We have now discovered an aluminum-phosphinimine complex which may be used to catalyze the polymerization of ethylene in the absence of transition metals.